Truss Rise Calculation for 9 Metre Span

The question asks us to determine the rise of a truss given its effective span is 9 metres. The rise of a truss is the vertical distance from the support level (or chord level) up to the highest point of the top chord at the centre of the span. The effective span is the horizontal distance between the centres of the supports.

In structural engineering, particularly for roof trusses, a common practice is to design the truss with a specific rise-to-span ratio. A widely used ratio for many standard roof trusses is 1/4.

Using this standard rise/span ratio, we can calculate the rise as follows:

• Effective Span = 9 metres
• Standard Rise/Span Ratio = 1/4

The formula to find the rise is:

\text{Rise} = \text{Effective Span} \times \text{Rise/Span Ratio}

Substituting the given values:

\text{Rise} = 9 \text{ metres} \times \frac{1}{4}

\text{Rise} = \frac{9}{4} \text{ metres}

\text{Rise} = 2.25 \text{ metres}

Therefore, based on a standard rise/span ratio of 1/4, the rise of a truss with an effective span of 9 metres would be 2.25 metres.